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kbc.c: Fix delay 0 when typing slowly #91

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Merged
mkopec merged 1 commit into from
Aug 3, 2026
Merged

kbc.c: Fix delay 0 when typing slowly #91

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30 changes: 22 additions & 8 deletions src/board/system76/common/kbc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -83,14 +83,20 @@ static const uint16_t kbc_typematic_period[32] = {
};
// clang-format on

static uint8_t kbc_buffer[32] = { 0 };
static uint8_t kbc_buffer[64] = { 0 };
static uint8_t kbc_buffer_head = 0;
static uint8_t kbc_buffer_tail = 0;

static bool kbc_buffer_privacy = false;
static uint32_t kbc_buffer_privacy_last_time = 0;
static uint32_t kbc_buffer_privacy_release_at = 0;
static uint16_t kbc_buffer_privacy_delay = 0;

static void kbc_buffer_privacy_arm(uint32_t now) {
uint16_t max = (uint16_t)options_get(OPT_KB_PRIVACY_MAX_DELAY_MS);
kbc_buffer_privacy_delay = (max == 0) ? 0 : (uint16_t)(nondeterministic_rng() % max);
kbc_buffer_privacy_release_at = now + kbc_buffer_privacy_delay;
}

static bool kbc_buffer_pop(uint8_t *scancode) {
if (kbc_buffer_head == kbc_buffer_tail) {
return false;
Expand All @@ -101,17 +107,24 @@ static bool kbc_buffer_pop(uint8_t *scancode) {
}

static bool kbc_buffer_push(uint8_t *scancodes, uint8_t len) {
uint8_t i;
//TODO: make this test more efficient
for (uint8_t i = 0; i < len; i++) {
for (i = 0; i < len; i++) {
if ((kbc_buffer_tail + i + 1U) % ARRAY_SIZE(kbc_buffer) == kbc_buffer_head) {
TRACE(" KB_Priv: buffer full, dropping %d scancodes\n", len);
return false;
}
}

for (uint8_t i = 0; i < len; i++) {
bool was_empty = (kbc_buffer_head == kbc_buffer_tail);
for (i = 0; i < len; i++) {
kbc_buffer[kbc_buffer_tail] = scancodes[i];
kbc_buffer_tail = (kbc_buffer_tail + 1U) % ARRAY_SIZE(kbc_buffer);
}

if (was_empty && options_get(OPT_KB_PRIVACY)) {
kbc_buffer_privacy_arm(time_get());
}
return true;
}

Expand Down Expand Up @@ -469,13 +482,14 @@ void kbc_event(struct Kbc *kbc) {
if (state == KBC_STATE_NORMAL) {
if (options_get(OPT_KB_PRIVACY)) {
uint32_t time = time_get();
if (time - kbc_buffer_privacy_last_time >= (uint32_t)kbc_buffer_privacy_delay) {
if (kbc_buffer_head != kbc_buffer_tail &&
(int32_t)(time - kbc_buffer_privacy_release_at) >= 0) {
TRACE("KB_Priv: delay of %d passed\n", kbc_buffer_privacy_delay);
if (kbc_buffer_pop(&state_data)) {
state = KBC_STATE_KEYBOARD;
kbc_buffer_privacy_last_time = time;
kbc_buffer_privacy_delay = (uint16_t)(nondeterministic_rng() %
options_get(OPT_KB_PRIVACY_MAX_DELAY_MS));
if (kbc_buffer_head != kbc_buffer_tail) {
kbc_buffer_privacy_arm(time);
}
}
}
} else {
Expand Down
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